A Katabatic wind, from the Greek word katabatikos meaning “going downhill”, is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity.
Such winds are sometimes also called fall winds. Katabatic winds can rush down elevated slopes at hurricane speeds (above 100 km per hour).
Katabatic winds are quiet strong apart from the winter also during the summer months and more specific during July and August where the Meltemi wind is blowing. They don’t affect the north part of the island as the majority of the winds are north, north west during the summer months.
The Meltemi wind was known by the old Greeks as the Etesian northern winds, and results from a high pressure system (>1025) laying over the Balkan/Hungary area and a relatively low pressure (<1010) system over Turkey.
Although this katabatic wind can bring very bad kayak conditions on multi day trips it also provides cooling, low humidity and good visibility.
Furthermore, it can be characterized as one of the few Mediterranean winds that do not necessarily die out at the end of the day and last for days without a break and this is why is very important the local knowledge when planning a long sea kayak expedition especially if you are planning to do an open crossing to any of the islands that are close by Crete like Paksimadia.
Typical weather associated with a meltemi event is dry with clear skies. Especially during the high season (July to August) a meltemi is heralded by scattered altocumulus and sometimes orographic clouds on the lee side of islands during the previous day. Typically a meltemi is accompanied by a sudden drop in humidity, improved visibility and a raise in atmospheric pressure.
A more scientific explanation of the katabatic winds can be seen in this article written by NASA.